What would happen if everybody wants to exchange for a real money?
Does everybody mean all people? I think that will not be a problem

I consider it not fair to mine cryptocurrencies?
It is still fair to mine cryptocurrencies because not all miners want to sell their mined coins, especially if they are still not profitable. They will still hold the coin until the price reaching the highest price they want.
If it is so good why there is a need for exchange rate to the real money?
Do you think people do not want to make a profit? They use the exchange to make money from the gap price. They will buy when the price is at a low price and will sell when the price is at a high price. That will still be like that.
Why recently I needed to block about 30 phone numbers constantly calling me to invest money in cryptocurrency?
Do you share your numbers with people you do not know? From where do they know your numbers?
Is it going to finish soon because of having probblems not to be fed this pyramide game with real money?
No, I do not think it will finish soon because I think crypto still has a long journey and maybe we will not see what happens to crypto in the future because we are all dead.